Various types of electrical apparatus, such as microprocessors, memory systems and arrays, computation circuits, and the like, operate in accordance with fixed clock signals. It is well known that such apparatus should be reset to a predetermined state after interruption of supply voltage. In order to reset the electronic apparatus, it has previously been proposed to generate a short, usually sharp voltage pulse upon energization of the apparatus, which is used as a reset pulse to reset the apparatus to the defined predetermined state. It has been found that such resetting will not, however, necessarily have the desired effect since a clock generator which, frequently, is powered by the same source as the microprocessor, will have not have started full oscillation at the time the reset pulse is received in the remainder of the apparatus. It is thus possible that undefined, stray or interference pulses which might arise upon starting might interfere with the operation of the system, by simulating clock pulses, or being processed in the form of clock pulses. Such stray pulses would, then, cause operation of the electronic apparatus so that, when the actual clock pulses start, the state of the apparatus will not be as thought, that is, in the predetermined defined state, but rather in the random state as determined by such extraneous or stray pulses. Thus, voltage-dependent resetting of electronic control apparatus is often not sufficient to reset the apparatus to the predetermined state. The problem is particularly acute in connection with automotive-type microprocessor control systems due to the frequent and random interruption of power supply thereto. Upon removal of all electrical power from the vehicle, for example upon opening of a main switch, or removal of the battery, operation of the microprocessor is terminated; likewise, the clock signal generator which furnishes predetermined clock signals is shut down. Restarting of the clock signal, as well as the microprocessor, will occur at random times, as determined and desired by the operator of the vehicle. It is important that the microprocessor start operation from a predetermined state in order to properly process sensed signals derived from engine sensors, for example.